Desperate help needed

My girlfriend runs her business from home and every thing is stored on her computer last night she right clicked on the desktop > arrange icons by > and then by mistake she clicked on lock web items on desktop. She now has no desktop I can't right click on the desktop any more to try and reverse what she has done. the system keeps crashing whenever I try to do anything and she manged to restore it back to an earlier date but its exactly the same. Her systems running XP home 1.8ghz processor with 756gb ram if this makes any difference.
Thanks in advance

Just adding to Overwhelmed's post...
Do this first:
MyWebSearch Search Assistant - Go to Add/Remove programs and remove MyWebSearch...
and then run thru that list of hijackthis entries.
Note: this entry is okay, it is just up to you whether you want to have that browser button:
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~3\OFFICE11\REFIEBAR.DL

Thanks everyone for your help I ended taking every thing off she needed in safe mode and formated it. She's back up and running now with a fresh intall and all her programs and documents back on. Thanks again.